Die jaw inserts are used to clamp tubing in tube cutoff machines during the severing operation. They are typically bolted into a die carriage assembly in two opposing mirrorimage pairs which move toward one another to clamp the tube and away from one another to release the tube. The two pairs are axially spaced to accommodate a severing blade which is driven through the tube by a ram.
The die jaw inserts are subject to wear and disfigurement over extended periods of use due to the contact with the tubing as well as the action of the severing blade. Close tolerances must, however, be maintained for successful operation of the cutoff machine. Therefore, the die jaw inserts are frequently replaced.
There are, of course, many sizes and configurations for the inserts. In the past, die jaw inserts were typically manufactured only on receipt of an order, rather then made up in advance and stored as inventory. Thus, a considerable time delay was often necessary between the receipt and fulfillment of an order.
The inserts could, of course, be prefabricated to a certain degree using prior art techniques; i.e., the blanks may be roughed-out but the clamping aperture may not be formed until the exact size requirement is known. Thus, the heat treating process to harden the inserts must also be delayed, for to preharden the blank makes the aperture too difficult to form using conventional machining techniques. As a result, the bulk of the fabrication process steps were performed after, rather than before, an order was received.